ABSTRACT
This study aimed to evaluate the diagnostic accuracies for pleural fluid tests that discriminate between transudative and exudative pleural effusion. A prospective evaluation of 78 patients with pleural effusion of different etiologies was done. The criteria showed the best results in this series, four effusions only were misclassified [three transudates and one exudate]. The number of misclassified effusions in other criteria was seven by PF cholinesterase [three transudates and four exudates], six by the P/S cholinesterase [four transudates and two exudates], six by PF cholesterol [one transudate and five exudates] and five by PF/S cholesterol ratio [two transudates and three exudates]. It was concluded that the criteria of Light et al. were the best method for distinguishing exudates from transudates